The present invention generally relates to shredding, comminuting, shearing or chopping solid materials, such as scrap vehicle tires, scrap insulated electrical conductors; used containers; and other solid waste materials required to be reduced into pieces prior to permanent disposal, recycling or other utilization.
Typically, prior machines for shredding tires or other solid waste materials employ a pair of oppositely rotating rotors fitted with interdigitated cutting discs, wherein the cutting discs on each rotor are maintained in spaced relation axially thereof by spacer rings. In order to facilitate maintenance of these machines, it has been common practice to fabricate each cutting disc from a mounting disc, which is keyed for rotation with a drive shaft of the rotor and has a peripheral surface formed with a plurality of uniformly arranged pockets or mounting recesses, and a plurality of cutter knives individually, removably clamped within the pockets by screwed threaded mounting bolts extending radially inwardly through the cutter knives and into the mounting disc. Material tending to collect between adjacent cutting discs is removed by stationary comb-like stripper plates or driven stripper rollers arranged in interdigitated relation with the cutting discs. Comminuted material may be passed through a screening or classifying device and, if required, again passed between the rotors until the materials are reduced to a given predominating size.
Machines of the type described are constructed and operated to reduce tires to pieces having a predominating size whose maximum dimension is determined by the widthwise or axial dimensions of the cutting discs. Typically, this maximum dimension is about two inches in that the size of the mounting bolts required to clamp the cutter knives to the mounting disc effectively limits the minimum widthwise dimension of the knives, and thus the cutting discs, to about two inches.
Machines of this general construction are disclosed by way of example in U.S. Pat. Nos. 3,931,935; 4,684,071 and 4,854,508.